In recent years, infrared detection technology has developed rapidly in military and civil fields, and various infrared detectors have also become increasing demands in the market. Thermopile infrared detectors, which have characteristics such as low cost, simple manufacturing process, no need of addition of bias voltage and no 1/f noise, and etc., are widely used in various infrared detection systems.
A thermopile infrared detector utilizes Seebeck effect, with hot junction and cold junction designed on the surface of a semiconductor substrate. There is an infrared absorption layer in the hot junction area, responsible for absorbing infrared radiation (generally in a wavelength range of 8-14 um) of an object that needs to be detected. The infrared absorption layer generates heat due to absorption of infrared radiation and conducts the heat to the hot junctions, with a temperature difference generated between the hot junctions and the cold junctions. The cold junctions are on the semiconductor substrate and has the same temperature as ambient temperature. By means of the Seebeck effect, an electric potential difference is generated between two electrodes of the thermopile infrared detector that are connected to the hot junctions and the cold junctions respectively. By detecting the electric potential difference, size of the infrared radiation of the object to be detected can be detected, and then surface temperature of the object to be detected can be given by combining parameters such as emissivity of the object to be detected, an optical system, a thermal conversion efficiency, and the like.
Generally, the thermopile infrared detector needs to be packaged in vacuum or in low-pressure gas after it has been manufactured, to reduce thermo-convective interference caused by air to the infrared absorption layer of the detector and improve sensitivity and stability of the detector. A traditional infrared detector is packaged mostly by a TO (Transistor Outline) can, FIG. 1 is a schematic diagram of a device of the packaged thermopile detector, in which FIG. 1 (A) is a bottom view, and FIG. 1 (B) is a side view. In the traditional TO package form, the infrared detector is placed and secured at the bottom of the TO tube, with a TO can having an infrared filter sealed on the top thereof, the infrared filter is responsible for filtering various needless optical wavelength. The TO can is vacuumized inside or is filled with the low-pressure gas, with several pins that are connected to the electrodes of the infrared detector being elicited at the bottom of the TO tube for the use of testing.
It should be noted that, the above introduction to the background is merely for the convenience of clear and complete description of the technical solution of the present application, and for the convenience of understanding of persons skilled in the art. It cannot be regarded that the above technical solution is commonly known to persons skilled in the art just because that the solution has been set forth in the background of the present application.